NSW electricity network performance report · 2015. 6. 26. · 2 | Electricity Network Performance Report 2009-10 Table 1.1 – Network Operator Statistics Network Operator Statistics

NSW electricity network performance report

2009/ 10

ii | Electricity Network Performance Report 2009-10

Contents

1. Profile .................................................................................................................................. 1

2. Network Management ........................................................................................................... 4

2.1 Overview .................................................................................................................... 4

2.2 Independent Appraisal Process.................................................................................... 4

2.3 Network Complaints .................................................................................................... 4

3. Network Planning ................................................................................................................. 6

3.1 Overview .................................................................................................................... 6

3.2 System Design Criteria (Planning Standards) ................................................................ 8

3.3 Demand Management ............................................................................................... 10

4. Asset Management ............................................................................................................. 14

4.1 Overview .................................................................................................................. 14

4.2 Technical Service Standards ..................................................................................... 16

4.3 Transmission Performance ........................................................................................ 17

5. Network Safety ................................................................................................................... 21

5.1 Overview .................................................................................................................. 21

5.2 Serious Electricity Network Accidents (Public) ............................................................. 24

5.3 Actionable Electricity Network Safety Incidents (Public) ............................................... 24

5.4 Serious Electricity Network Accidents (Network Worker) .............................................. 25

5.5 Actionable Electricity Network Safety Incidents (Network Workers) ............................... 25

6. Bush Fire Risk Management ............................................................................................... 26

6.1 Bush Fire Risk Management Plan .............................................................................. 26

6.2 Bush Fire Risk Management Performance .................................................................. 26

6.3 Audits....................................................................................................................... 27

6.4 Preventative Programs .............................................................................................. 27

6.5 Proactive Programs ................................................................................................... 27

6.6 Aerial Laser Surveys ................................................................................................. 27

7. Public Electrical Safety Awareness ...................................................................................... 29

8. Power Line Crossings of Navigable Waterways .................................................................... 30

iii | Electricity Netw ork Performance Report 2009-10

Tables

Table 1.1 – Network Operator Statistics......................................................................................... 2

Table ‎2.1 – Complaints Received Regarding Network Issues .......................................................... 5

Table ‎4.1 – Transmission Asset Availability (%) Trend.................................................................. 18

Table ‎4.2 – Network Reliability Trend (Off Supply Event Numbers) ................................................ 18

Table ‎4.3 – Outage (Un-Planned) Average Duration (Minutes) Trend ............................................ 18

Table ‎4.4 – Connection Point Interruptions (Unplanned) Current Year ........................................... 19

Table ‎4.5 – Connection Point Numbers End Current Year............................................................. 20

Table ‎5.1 – Serious Electricity Network Accidents (Public) Trend .................................................. 24

Table ‎5.2 – Actionable Safety Incidents (Public) on the Electricity Network Summary Trend ........... 24

Table ‎5.3 – Serious Accidents (Network Worker) on the Electricity Network Trend ......................... 25

Table ‎5.4 – Actionable Safety Incidents (Network Workers) on the Electricity Network

Summary Trend ...................................................................................................... 25

Table 8.1 – Power Line Crossings of Navigable Waterways Summary ........................................... 30

1 | Electricity Network Performance Report 2009-10

Introduction

This Electricity Network Performance Report has been prepared by TransGrid to fulfil the

requirements of the Electricity Network Operator reporting regime and the Electricity Supply (Safety

and Network Management) Regulation 2008.

This report has been independently appraised in accordance with the requirements of the Industry &

Investment NSW Report Outline. The Appraisal Report confirmed that this Report is complete and that

the data presented can be relied upon by Industry & Investment NSW for carrying out performance

analysis.

1. Profile

TransGrid is Australia‟s largest transmission company with its network comprising some 12,609

kilometres of high voltage transmission line and underground cables, as well as 91 substations and

switching stations, worth over $4.2 billion.

TransGrid is responsible for planning and developing the New South Wales transmission system to

deliver the requirements of customers within the state and to facilitate operation of the National

Electricity Market.

TransGrid‟s system operates at voltage levels of 500, 330, 220 and 132kV. TransGrid‟s substations

and power station switchyards are located on land owned by TransGrid and the transmission lines of

steel tower, concrete or wood pole construction are generally constructed on easements acquired

across private or public land.

TransGrid has a number of key challenges including the management of a multi -billion dollar capital

works program for 2009-2014 aimed at meeting the ever-increasing demand for electricity and

securing the nation‟s energy future.

TransGrid has staff strategically based at locations throughout NSW in order to meet the day to day

operation and maintenance requirements as well as being able to provide emergency response. The

main administrative office is located at 201 Elizabeth Street, Sydney. Field staff are co -ordinated from

major depots located at the Metropolitan Centre in Western Sydney and at Newcastle, Tamworth,

Orange, Wagga Wagga and Yass.


Table ‎1.1 – Network Operator Statistics

Network Operator Statistics

At End 2008/09 At End 2009/10

Customer Numbers (Total) 13 13

Maximum Demand (Aggregated System MW)1 14,368 14,051

Energy Received to Year End (GWh)1 73,216 72,814

System Loss Factor (%)2 3.6% 3.1%

High Voltage Overhead (km)3 12,445 12,609

High Voltage Underground (km)3 47 47

Substation (Number) 85 91

Structures (Number)4 36,543 36,483

Poles (Number)5 39,394 38,480

Employees (Full Time Equivalent Number) 995 1017

Contractors (Full Time Equivalent Number) 479 287

Notes: 1. Maximum demand is the highest coincident summated demand supplied by the network. In previous reports only scheduled demand and energy was reported. With increased semi and non-scheduled generation in NSW, and in

accordance with guidelines from AEMO, TransGrid is now reporting Native Energy and Demand (both historical and forecast) series in its Annual Planning Report and in this report. This in turn is applied by AEMO in developing its Electricity Statement of Opportunities (ESOO) and National Transmission Netw ork Development Plan (NTNDP).

2. The System Loss Factor is the difference between electricity received by the network and electricity delivered to

customers divided by electricity received by the network (allow ing for embedded generation), expressed as a percentage.

3. Distances for overhead and underground lines are circuit km.

4. The number of structures includes both lattice towers and structures comprised of one or more poles.

5. Pole numbers are total number of individual poles, whether forming a single or multi pole s tructure.


Figure 1.1 – Network Map


2. Network Management

2.1 Overview

TransGrid‟s vision is to be recognised as a world class electricity transmission company. It is

committed to providing a safe working environment and ensuring the reliability of its electricity

transmission network. TransGrid‟s success in managing its assets is reflected in its transmission

system reliability of over 99.999%, making it a leading performer among Transmission Network

Service Providers.

TransGrid‟s asset management and maintenance strategies are driven by its Network Management

Plan 2009-2014 Revision 1. In accordance with the Electricity Supply (Safety and Network

Management) Regulation 2008 the Plan comprises chapters detailing Network Safety and Reliability,

the Public Electrical Safety Awareness Plan, Customer Safety Installation Plan and Bush Fire Risk

Management Plan.

This Plan provides a basis for ongoing analysis within TransGrid and for continual improvement of the

transmission system while also providing an authoritative vehicle for dissemination of information to

TransGrid‟s customers, stakeholders and employees.

TransGrid has also published a 30 Year Asset Management Plan covering the period from 2009 to

2039. The 30 Year and Five Year Plans quantify TransGrid‟s medium and long term strategies for

asset management and are used to determine budget forecasts.

Ongoing management strategies aimed at the achievement of TransGrid‟s mission are the

maintenance and development of Asset Maintenance Policies and Strategies in the framework of an

accredited Quality Documentation system, a system of Quarterly Asset Performance Reviews, regular

Technical Performance Assessments and audits, and extensive benchmarking studies.

2.2 Independent Appraisal Process

This report has been subject to an independent appraisal carried out in accordance with Attachment C

of the Industry & Investment NSW Report Outline.

2.3 Network Complaints

There were 20 complaints registered during 2009/10.

Nine complaints were associated with the establishment of Wollar switching station and Wollar-

Wellington 330kV transmission line. The complaints related to construction activity including noise,

dust caused by truck activity, detrimental effects to farming activities, access arrangements such as

gates being left open and compensation. Complaints have been managed and resolved by TransGrid

local staff managing the project.

Seven complaints were associated with the Dumaresq - Lismore 330kV transmission line project.

Complaints generally related to the loss of li festyle, reduced property values, aesthetic impacts,

potential health impacts and tourism impacts that may exist if the proposed line is built. These

complaints are being addressed as part of the ongoing community consultation for the project.


Two complaints were associated with communication tower upgrades, one relating to the visual

amenity of a new tower and one relating to dust caused by truck activity.

Two complaints were associated with environmental and security matters at Sydney East substation.

These related to the use of chemicals for vegetation management rather than cutting of grass, and

dumping of bottles by the general public in areas around the substation.

All of these complaints have been addressed. The issues raised with respect to the Dumaresq –

Lismore project will be dealt with as part of the continuing consultation program for the project.

Complaint Performance Data

Table ‎2.1 – Complaints Received Regarding Network Issues

Complaints Received Regarding Network Issues

Years 2005/06 2006/07 2007/08 2008/09 2009/10

Complaints Total 21 9 27 92 20

Complaints Regarding Vegetation Management

3 2 4 1 1

A complaint means a written or verbal expression of dissatisfaction about an action, a proposed action, or a failure to act by a

network operator, its employees or contractors. This includes failure by network operators to observe their published or agreed practices or procedures. Enquiries have not been included.


3. Network Planning

3.1 Overview

TransGrid is responsible for the planning and development of transmission networks in New South

Wales in two interrelated roles.

Firstly, it has been nominated by the NSW Minister for Energy to be the Jurisdictional Planning Body

(JPB) for NSW in the National Electricity Market. In this role it:

provides jurisdictional information to the Australian Energy Market Operator (AEMO) for input

to the Electricity Statement of Opportunities (ESOO) and National Transmission Network

Development Plan (NTNDP);

carries out an Annual Planning Review during which it:

prepares an Annual Planning Report (APR) for NSW;

holds a public forum that considers the APR and related transmission planning matters;

reports to the Minister for Energy on matters arising from the Annual Planning Review;

and

reports to the Minister for Energy on matters arising from the ESOO and NTNDP.

Secondly, it is registered with AEMO as a Transmission Network Service Provider (TNSP) in the NSW

region of the National Electricity Market (NEM). The National Electricity Rules ( NER) require

TransGrid, as a TNSP, to:

analyse the future operation of its transmission network to determine the extent of any future

network constraints;

conduct annual planning reviews with DNSPs to determine the extent of any emerging

constraints at points of connection between the TNSP‟s network and the DNSPs‟ networks;

carry out joint planning with DNSPs to determine options for the relief of constraints that can

be considered by Registered Participants and interested parties;

coordinate a consultative process for consideration and economic analysis of the options in

accordance with the Australian Energy Regulator‟s (AER's) regulatory test, if required;

on the basis of the consultative process and economic analysis determine the recommended

option for network augmentation if required;

after resolution of any disputes concerning the recommended option, arrange for its

implementation in a timely manner; and

prepare and publish an Annual Planning Report by June 30 of each year.

The NER require the Annual Planning Report to include:

results of annual planning reviews with DNSPs during the present year;

load forecasts submitted by DNSPs;

planning proposals for future connection points;

forecast and quantification of constraints over 1, 3 and 5 years;


plans and dates to issue a request for proposal for a non-network alternative;

summary information for proposed augmentations;

summary information for proposed replacement transmission network assets; and

consultation reports on proposed new small transmission network assets.

These obligations are described more fully in Chapter 5.6 of the NER and the AER's regulatory test.

Figure 2.1 illustrates the main tasks and interrelationship of TransGrid's dual roles.

Figure 2.1 – TransGrid’s Planning Roles

To meet these obligations, TransGrid incorporates appropriate elements of the New South Wales

Government‟s Total Asset Management (TAM) System regardi ng inter-agency plans and strategic

planning (refer to Section 4.1 of this document).


3.2 System Design Criteria (Planning Standards)

Under NSW legislation, TransGrid has responsibilities that include planning for future NSW

transmission needs, including interconnection with other networks.

In addition, as a TNSP in the NEM, TransGrid is obliged to meet the requirements of Schedule 5.1 of

the NER. In particular, TransGrid is obliged to meet the requirements of clause S 5.1.2.1:

“Network Service Providers must plan, design, maintain and operate their transmission networks

… to allow the transfer of power from generating units to Customers with all facilities or equipment

associated with the power system in service and may be required by a Registered Participant

under a connection agreement to continue to allow the transfer of power with certain facilities or

plant associated with the power system out of service, whether or not accompanied by the

occurrence of certain faults (called “credible contingency events”).

The NER sets out the required processes for developing networks as well as minimum performance

requirements of the network in a range of areas including:

a definition of the minimum level of credible contingency events to be considered;

the power transfer capability during the most critical single element outage. This can range

from zero in the case of a single element supply to a portion of the normal power transfer

capability;

frequency variations;

magnitude of power frequency voltages;

voltage fluctuations;

voltage harmonics;

voltage unbalance;

voltage stability;

synchronous stability;

damping of power system oscillations;

fault clearance times;

the need for two independent high speed protection systems;

automatic reclosure of overhead transmission lines; and

rating of transmission lines and equipment.

In addition to adherence to NER and regulatory requirements, TransGrid‟s transmission planning

approach has been developed taking into account the historical performance of the components of the

NSW system, the sensitivity of loads to supply interruption and state -of-the-art asset maintenance

procedures. It has also been recognised that there is a need for an orderly development of the system

taking into account the long-term requirements of the system to meet future load and generation

developments.

TransGrid consults with NEM Registered Participants and interested parties during the planning

process and in determining proposals for network augmentations.


TransGrid‟s planning obligations are also interl inked with the licence obligations placed on Distribution

Network Service Providers (DNSPs) in NSW. TransGrid must ensure that the system is adequately

planned to enable their licence requirements to be met.

In meeting these obligations TransGrid‟s approach to network planning is socially and economically

based and is consistent with both the NER and the regulatory test. It includes consideration of non -

network options such as demand side response and DM and/or embedded generation, as an integral

part of the planning process. Joint planning with DNSPs, directly supplied industrial customers,

generators and interstate TNSPs is carried out to ensure that the most economic options, whether

network options or non-network options, consistent with customer and community requirements are

identified and implemented.

TransGrid has traditionally planned the network to achieve supply at least community cost, without

being constrained by State borders or ownership considerations. Prior to commencement of the NEM

transmission augmentations were subjected to a cost-benefit assessment according to NSW State

Treasury guidelines. A similar approach is applied in the NEM where the AER‟s regulatory test

(Regulatory Investment Test for Transmission or RIT-T from 1 August 2010) is applied to meet the

requirements of Chapter 5 of the NER.

In addition to meeting requirements imposed by the NER, environmental legislation and other statutory

instruments, TransGrid is expected by the NSW jurisdiction to plan and develop its transmis sion

network on an “n-1” basis. That is, unless specifically agreed otherwise by TransGrid and the affected

distribution network owner or directly connected end-use customer, there will be no inadvertent loss of

load (other than load which is interruptible or dispatchable) following an outage of a single circuit (a

line or a cable) or transformer, during periods of forecast high load.

In fulfilling this obligation, TransGrid must recognise specific customer requirements as well as

AEMO‟s role as system operator for the NEM. To accommodate this, the standard “n-1” approach can

be modified in the following circumstances:

Where agreed between TransGrid and a distribution network owner or major directly

connected end-use customer, agreed levels of supply interruption can be accepted for

particular single outages, before augmentation of the network is undertaken (for example

radial supplies).

Where requested by a distribution network owner or major directly connected end-use

customer and agreed with TransGrid there will be no inadvertent loss of load (other than load

which is interruptible or dispatchable) following an outage of a section of busbar or coincident

outages of agreed combinations of two circuits, two transformers or a circuit and a transformer

(for example supply to the inner metropolitan/CBD area of Sydney).

The main transmission network, which is operated by AEMO, should have sufficient capacity

to accommodate AEMO‟s operating practices without inadvertent loss of load (other than load

which is interruptible or dispatchable) or uneconomic constraints on the energy market. At

present AEMO‟s operational practices include the re-dispatch of generation and ancillary

services following a first contingency, such that within 30 minutes the system will again be

“secure” in anticipation of the next critical credible contingency.

In 2005 mandatory licence conditions were introduced on DNSPs which set out certain reliability

standards for sub-transmission and distribution networks. The licence conditions specify “n-1, 1

minute” reliability standards for sub-transmission lines and zone substations supplying loads greater

than or equal to specified minimums, eg 15 MVA in urban and non-urban areas. These requirements


imply a consequential obligation on TransGrid to provide a commensurate level of reliability in its

network supplying NSW DNSPs.

Accordingly, Country Energy has requested TransGrid to provide a commensurate reliability standard

at connection points to its network, i.e. “n-1, 1 minute” reliability where Country Energy‟s maximum

demand is greater than or equal to 15 MVA.

The jurisdictional requirements and other obligations described above also require the following to be

observed in planning:

At all times when the system is either in its normal state with all elements in service or

following a credible contingency:

Electrical and thermal ratings of equipment will not be exceeded; and

Stable control of the interconnected system will be maintained, with system voltages

maintained within acceptable levels.

A quality of electricity supply at least to NER requirements is to be provided;

A standard of connection to individual customers determined by Connection Agreements is to

be provided;

As far as possible, connection of a customer is to have no adverse effect on other connected

customers;

Environmental constraints are to be satisfied;

Acceptable safety standards are to be maintained; and

The power system in NSW is to be developed at the lowest cost possible whilst meeting the

constraints imposed by the above factors.

Consistent with a responsible approach to the environment, it is also aimed at reducing system energy

losses where economic.

A further planning consideration is the provision of sufficient capability in the transmission network to

allow components to be maintained in accordance with TransGrid‟s asset management strategies.

3.3 Demand Management

3.3.1 Consideration of Non-Network Options by TransGrid

The Annual Planning Report provides advance information to the market on the nature and location of

emerging network constraints. This is intended to encourage interested parties to formulate and

propose feasible non-network options including Demand Management (DM), Demand Side Response

(DSR) and local or embedded generation options, to relieve the emerging network constraints. The

advantages that non-network options offer in relieving transmission network constraints are that they

may:

reduce, defer or eliminate the need for new transmission or distribution investment; and/or

reduce, defer or eliminate the costs and environmental impacts of construction and operation

of fossil fuel based power stations.


TransGrid considers DM, local/embedded generation and bundled options on an equal footing with

network options when planning its network augmentations and applying the AER‟s regulatory test.

For any option to be considered during the evaluation and analysis process, it must be feasible and

capable of being implemented in time to relieve the emerging constraint.

For an option to be recommended for implementation after evaluation and analysis, it must satisfy the

regulatory test. It must also have a proponent who is committed to implement the option and to accept

the associated risks, responsibilities and accountabilities.

It is expected that DM and local generation options would emerge from joint planning with DNSPs,

from the market or from interested parties.

TransGrid‟s joint planning with NSW DNSPs provides a mechanism to identify opportunities for DM

and local/embedded generation options. The NSW DNSPs follow a similar process to TransGrid in

preparing planning reports for their networks, thereby providing another useful source of information

for proponents of DM and local generation options.

Demand Management or Demand Side Reponse

DM or DSR options may include, but are not limited to, combinations of the following:

Reduction in electricity demand at points of end-use through:

improved energy efficiency devices and systems;

thermal insulation;

renewable energy sources such as solar; and

alternative reticulated energy sources such as natural gas.

Reduction in peak electricity consumption at points of end-use through:

tariff incentives;

load interruption and reduction incentives;

arrangements to transfer load from peak to off-peak times;

energy storage systems;

standby generators; and

power factor correction equipment.

Embedded or Local Generation

Embedded or local generation options may include generation or cogeneration facilities located on the

load side of a transmission constraint. Alternative energy sources may include, but are not limited to:

bagasse;

biomass;

gas (e.g. natural gas or LPG);


hydro;

solar; and

wind.

Promotion of DM and Local Generation Alternatives by TransGrid

TransGrid actively promotes DM and local generation alternatives through:

identifying opportunities for DM and local generation options through joint planning with the

DNSPs and engaging expert external consultants where warranted;

informing the market of constraints via the Annual Planning Report and consultations for

alleviating individual constraints;

participation in initiatives and reviews that include consideration of DM and its relationship to

the development of electricity networks; and

joint sponsorship of research projects involving DM and embedded generation.

3.3.2 Recent Non-Network Projects

Western 500 kV Conversion Non-Network Project

TransGrid undertook to acquire 350 MW (effective capacity) of network support services for the

Newcastle – Sydney – Wollongong area from non-network sources. Following a competitive tendering

process three proponents were selected to form a portfolio consisting of a large industrial load, a

demand management aggregator and an embedded generator.

TransGrid contracted 350 MW of network support from this portfolio to ensure that it met its planning

and reliability obligations during summer 2008/ 09 while allowing for deferral of the Western 500 kV

conversion project by one year to 2009/10.

The AER approved the pass-through of network support payments made to the service providers. At

the conclusion of the support period (March 2009) TransGrid adjusted its 2009/10 TUOS payments

returning in excess of $14 Million in unused funding for network support to its customers.

It was the largest ever acquisition of network support from non-network sources in the NEM to defer a

major capital works program while maintaining the reliability of supply to customers.

3.3.3 Future DM and other Non-Network Projects

DM projects and initiatives that TransGrid is likely to implement in the next five years include:

Network support to cover operational risk management measures for the Sydney Inner

Metropolitan load area at times of peak demand [summer of 2012/13]; and

Projects with the NSW DNSPs to cooperate on demand management innovation for which

TransGrid has signed agreements. Joint projects include initiatives to reduce peak demand

and some research and development projects.


Other non-network projects that are likely to be implemented are:

Provision of reactive power for main system network support which may come from non-

network sources;

Provision of network support, possibly from non-network sources, to improve the power

transfer capability between the Snowy Mountains and Yass/Canberra. This may include

implementation of a special system protection scheme; and

Provision of Network Support and Control Ancillary Service (NSCAS). The AEMC is currently

consulting on the future framework in this regard which may require TNSPs to procure and

deliver reactive power capability for main system security and reliability. Part of the NSCAS

may come from non-network sources.

3.3.4 Price Signals and Financial Incentives to Encourage DM and Local Generation

TransGrid is a provider of bulk transmission network services and is best placed to implement „bulk‟

DM options. For example, it is the customers connected at the transmission voltage levels and

electricity distribution businesses that are exposed to and respond to transmission pricing structures.

These pricing structures reflect the requirements of the National Electric ity Rules and the associated

Transmission Pricing Methodology approved by the AER.

Among these structures, the monthly maximum demand charge is designed to encourage demand

side response at the time of maximum demand on the transmission network.

In addition, TransGrid can and does provide financial incentives via direct payments under network

support contracts with wholesale suppliers of demand reductions such as larger end users or

embedded generators or DM aggregators. Contractual payments to smaller suppliers of DM are now

proving practical for TransGrid with the advent of DM aggregators. Significantly, the regulatory

incentive framework is evolving to provide improved commercial incentives for TransGrid to engage in

these activities.

The full impact of transmission pricing structures, as well as distribution sector DM activities, is not

always obvious at TransGrid‟s „bulk‟ connection points with electricity DNSPs. This is because this

level of demand response is „embedded‟ in the aggregated actual demand at these connection points.

The forecast demand at these connection points, provided by the electricity DNSPs for transmission

planning purposes, also includes anticipated demand response within each DNSP‟s franchise area.


4. Asset Management

4.1 Overview

TransGrid is constantly striving to optimise its asset management performance as a means of

achieving its corporate vision “to be recognised as a world-class electricity transmission company” and

meeting its customers‟ expectations of system reliabil ity and quality of supply. This involves the

development and ongoing review of Asset Management Policies and Strategies for the construction,

maintenance, refurbishment, replacement/renewal and disposal of the full range of network assets.

To accomplish this mission, TransGrid has developed an Asset Management model that is based on

the New South Wales Government‟s Total Asset Management (TAM) Model as promulgated in 2006.

TransGrid‟s model is shown in Figure 4.1.

Figure 4.1 – TransGrid’s Asset Management Model


As a service delivery utility, TransGrid‟s approach is to apply the various elements of the TAM model,

including strategies for Planning & Service Delivery, Assets, Capital Investment, Asset Maintenance

and Asset Disposal, as well as the recommended implementation Plans for HR, IT, Procurement and

the legislative, community and stakeholder forms of direction. In addition, TransGrid strives to meet its

service delivery obligations as determined by the AER in the form of Reliability and Availability while

also meeting its corporate and community commitments to safety and the environment.

To support this objective, TransGrid has initiated or maintained a number of strategies during the year:

The review of maintenance policies and asset management strategies using a risk management

approach, identifying the criticality, reliability, risks and exposures associated with particular

courses of action.

Achievement of a consistently high standard of asset maintenance is facilitated by TransGrid‟s

continued certification to ISO 9001 of its Quality Documentation system. Despite the large

geographical distances between Regions and their assets, there is confidence in the effective

application of consistent policies across the network.

Quarterly Asset Performance Reviews are conducted by maintenance, operating, asset

management and design staff to specifically review the performance of the network assets during

the previous three months. This involves the detailed analysis of all forced and emergency

outages during the period, as well as a review of the long term availability and reliability trends to

determine any issues requiring further investigation. Review meetings were held in September

2009, November 2009, February 2010 and May 2010.

Technical Performance Assessments are carried out annually on each Region to audit the

technical standard and completeness of the maintenance performance. Independent internal

auditors with specialist knowledge of the maintenance functions for different asset types conduct

these assessments. A formal report detailing observations and business risks is prepared, with a

follow-up process to ensure that any issues identified are effectively addressed. During the year,

assessments were conducted at Northern Region/Newcastle (August 2009), Central

Region/Metropolitan (November 2009) and Southern Region/Wagga (March 2010).

TransGrid‟s maintenance performance in the Australasian and International sphere is monitored

through its regular participation in benchmarking studies. ITOMS (International Transmission

Operations & Maintenance Study) is a biennial study organised by a steering committee

representing twenty nine transmission organisations from Australasia, Europe, United Kingdom,

United States, South America and the Middle East, managed by the consulting group UMS. It

compares at a detailed level the comparative costs of individual maintenance functions and their

associated outage service levels. The results of these studies continue to provide insights into

other best performer organisations‟ work practices. This information is fed back into TransGrid‟s

reviews of its own practices and policies, completing the self -improvement cycle of asset

management. The most recent study TransGrid has participated in is the ITOMS 2009 study for

analysis of performance during the year 2008-2009, for which practices were discussed amongst

TNSPs in April 2010. TransGrid performed well in the benchmark, as the least cost transmission

organisation worldwide while maintaining above average service levels .

TransGrid‟s Reliability Steering Committee provides Executive oversight of all matters affecting

network and system performance. The committee convenes on a quarterly basis and reviews the

previous quarter‟s network performance in liaison with the Quarterly Asset Performance Review

Working Group and System Planning and Performance Review Working Group with an overall aim

of improving network reliability.


These and other asset management strategies which meet the TAM model are described in detail in

Chapter 1 of TransGrid‟s Network Management Plan 2009-2014 Revision 1, as follows: Planning and

Service Delivery (Section 3) and Asset Strategies (Section 4), including Asset Maintenance and

Operating Strategies (Section 4.1), Specific Asset Profiles and Strategies (Section 4.2) and Asset

Disposal Strategies (Section 4.3).

4.2 Technical Service Standards

TransGrid‟s main service standards of customer focussed network performance are those of reliability

and availability. In the incentive scheme administered by the AER, average unplanned outage

restoration time and market impact of transmission constraints are also reported.

4.2.1 Reliability

A customer‟s perception of a network provider‟s reliability performance is based on how often the

customer loses supply due to a temporary failure of network plant. The less often or less severe any

such losses, the better the perceived performance. The industry defines this reliability in „system

minutes‟. Simply put, any loss of supply event can be described as the number of minutes that the

total network would have to be down at the network‟s annual maximum demand to equate to the

amount of energy (MWh) that was not supplied. For example, in 2009/10, one (1) system minute

would have equated to 234.2 MWh.

TransGrid is subject to two reliability incentive parameters under the AER‟s Service Target

Performance Incentive Scheme (STPIS). The parameters are a count of the number of events for

which loss of supply is greater than 0.05 system minutes, and the number for which loss of supply is

greater than 0.25 system minutes.

4.2.2 Availability

TransGrid‟s connected customers perceive the network‟s availability as its readiness to effectively

transfer energy from the generators to the DNSPs. It is a measure of the total time all transmission

assets were in service compared to the theoretical ideal of all assets being in service for 100% of the

time.

Availability is impacted by the duration of planned outages for scheduled maintenance and capital

construction or replacement programs as well as unscheduled outages from plant failures. Higher

values of transmission availability may be achieved by minimisation of planned maintenance (through

optimisation of maintenance policy) and more effective co-ordination of all planned outages, as well as

improved maintenance practices to achieve fewer plant failures.

4.2.3 Average Outage Restoration Time

The average outage restoration time measures the time taken to return equipment to service after an

unplanned (forced or emergency) outage. It is calculated by summing the durations of unplanned

outages longer than one minute, and dividing by the number of those outages.

4.2.4 Market Impact of Transmission Congestion

Since July 2009 TransGrid has participated in the AER‟s new Market Impact of Transmission

Congestion (MITC) parameter, which measures the impact of transmission network outages on market


price. It provides an incentive to TransGrid to minimise transmission constraints, which inhibit the least

cost generation from being dispatched resulting in higher generation costs and higher electricity

prices. The intent of the parameter is for TNSPs to reduce the impact of their outages on market price

through outage scheduling, work practices and other methods.

The MITC parameter counts the number of 5 minute dispatch intervals in which constraints due to

planned or unplanned outages on TransGrid‟s transmission system cause more than a $10/MWh

increase to the spot price. The MITC scheme provides a bonus if the count of these dispatch intervals

is less than the performance level determined by the AER. There is presently no penalty applied if the

number of constrained dispatch intervals exceed the target.

4.2.5 Quality of Supply

TransGrid addresses its obligations to quality of supply in a manner set out in Section 3.2 (Reliability

Planning Standards) of this report and as required by Schedules S5.1a and S5.1 of the National

Electricity Rules, covering:

power frequency voltage;

voltage fluctuations;

voltage waveform distortion;

voltage unbalance; and

fault clearance times.

4.3 Transmission Performance

4.3.1 Reliability

For the 2009/10 year TransGrid experienced 17 Energy Not Supplied outages totalling 1.28 system

minutes. When converted to a percentage of energy delivered, this equates to a reliability exceeding

99.999%. There were four incidents with ENS greater than 0.05 system minutes and one incident with

ENS greater than 0.25 system minutes, compared to AER targets of four and one respectively.

4.3.2 Availability

For the 2009/10 year TransGrid achieved availabilities of:

Transmission Line Availability – 98.17% compared to AER target of 99.26%;

Transformer Availability – 98.60% compared to AER target of 98.61%; and

Reactive Plant Availability – 96.35% compared to AER target of 99.12%.

These represent the availability of transmission lines, transformers and reactive plant as reportable to

the AER. The below target value for transmission line availability is due mainly to the longer than

planned outage for the reconstruction of the 990 Yass to Wagga 132kV transmission line. The below

target value for reactive plant availability is largely due to some plant reaching its end of life, for which

there is a replacement project scheduled.


4.3.3 Market Impact of Transmission Congestion

In 2009/10 TransGrid recorded 1773 dispatch intervals under this parameter. This is an improvement

of 38% against the target of 2857 dispatch intervals, which was TransGrid‟s average performance in

the 2004-2007 period and used by the AER to set the target.

4.3.4 Connection Point Performance

Of TransGrid‟s fourteen connected customers, nine did not experience any unplanned outages

causing loss of supply or interruption to generation. Three distribution customers, Country Energy,

EnergyAustralia and Integral Energy, experienced loss of supply f rom unplanned outages. Two

generator customers, Macquarie Generation and Snowy Hydro, experienced interruptions to

generation.

Transmission Reliability Performance Data

Table ‎4.1 – Transmission Asset Availability (%) Trend

Transmission Asset Availability (%) Trend

Years

Objective 2005/06 2006/07 2007/08 2008/09 2009/10

Transmission Lines 99.26 99.47 99.44 98.55 98.44 98.17

Transformers 98.61 98.98 98.16 97.69 98.42 98.60

Reactive Plant 99.12 99.43 99.96 98.97 98.96 96.35

Note: 1. A measure of the circuit availability compared to the total availability if no outages had occurred.

2. Outages will generally occur for maintenance purposes and thus 100 per cent is inherently unachievable.

Table ‎4.2 – Network Reliability Trend (Off Supply Event Numbers)

Network Reliability Trend (Off Supply Event Numbers)

Years

Objective 2005/06 2006/07 2007/08 2008/09 2009/10

No. > 0.05 system minutes 4 3 1 3 3 4

No. > 0.25 system minutes 1 0 1 0 0 1

Table ‎4.3 – Outage (Un-Planned) Average Duration (Minutes) Trend

Outage (Un-Planned) Average Duration (Minutes) Trend

Years

Objective 2005/06 2006/07 2007/08 2008/09 2009/10

824 973 613 843 862 607


Table ‎4.4 – Connection Point Interruptions (Unplanned) Current Year

Connection Point Interruptions (Unplanned) Current Year

Connection Point Interruption Number Interruption Duration Total (Minutes)

Griff ith – 33kV 79C Darlington Point Feeder 1 164

Broken Hill – 22kV No.3 South Feeder 1 156

Broken Hill – 22kV No.4 Railw ay Town Feeder 1 156

Broken Hill – 22kV No.5 Talc St 2 Feeder 1 156

Broken Hill – 22kV No.6 Talc St 1 Feeder 1 156

Broken Hill – 22kV No.7 West Feeder 1 156

Broken Hill – 22kV No.8 Cockburn Feeder 1 156

Broken Hill – 220kV X4 Line 1 265

Beryl – 66kV 852 Dunedoo Feeder 1 4

Coleambally – 132kV No.1 Transformer 1 82

Coleambally – 132kV No.2 Transformer 1 82

Kempsey – 66kV 864 Telegraph Point Feeder 1 80

Kempsey – 66kV 0865 New ee Creek Feeder 1 80

Deniliquin – 66kV 821 Finley Feeder 1 4

Deniliquin – 66kV 822 Moulamein Feeder 2 64

Deniliquin – 66kV 845 Deniliquin Feeder 1 4

Deniliquin – 66kV 844 Barham Feeder 1 4

Deniliquin – 66kV No.6 Moama Feeder 1 4

Finley – 66kV 84A Jerilderie Feeder 2 226

Finley – 66kV 84B Finley Feeder 2 226

Balranald – 22kV No.1 Balranald Feeder 3 325

Balranald – 22kV No.2 Moulamein Feeder 2 245

Coffs Harbour – 66kV 703 Nana Glen Feeder 1 14

Coffs Harbour – 66kV 711 North Coffs Feeder 1 12

Koolkhan – 66kV 0825 Koolkhan PS Feeder 2 32

Koolkhan – 66kV 0826 Grafton Feeder 1 27

Koolkhan – 66kV 0896 Maclean Feeder 1 27

Sydney North – 132kV 250 Berowra Line 1 58

Walleraw ang 132 – 66kV 940 Warrimoo tee North Katoomba Feeder 1 72

Guthega – No.1 Generator 2 113

Guthega – No.2 Generator 2 113

Bayswater – No.1 Generator 1 251




Note: 1. This table provides a listing of customer connection points off supply events.

2. The list does not include load shed follow ing failure of the Bayswater current transformer on 2 July 2009, as this was shed by underfrequency relays in DNSPs‟ netw orks and at Tomago Aluminium rather than interruption to a connection point.

3. Events included in this list may have been excluded from the data shown in Table 4.2. See Attachment A of the

Industry & Investment NSW Report Outline for exclusion criteria.


Table ‎4.5 – Connection Point Numbers End Current Year

Connection Point Numbers End Current Year

Number of Connection Points (Total Number) 427


5. Network Safety

5.1 Overview

TransGrid‟s goal is zero injuries, occupational illnesses and incidents. Our first priority is the health

and safety of our people, our contractors, visitors and the public. Our strategies are aimed at

continually improving our performance and maintaining a major focus on risk management.

Our Health & Safety Management System is certified to Australian Standard AS/NZS 4801 and

TransGrid also holds a self insurer licence for workers compensation.

TransGrid‟s Health & Safety Management System is overseen by the Executive Occupational Health

and Safety (OHS) Committee which is chaired by the Managing Director and includes the General

Manager or senior management representative from each business unit. In addition, a number of

strategies during the year have been developed, implemented and monitore d to ensure the system is

effective and provides for continuous improvement. These include:

Safety Improvement Program;

Corporate Health and Safety Plan;

Safety Communications Steering Committee;

Quarterly Health and Safety Themes;

Annual Safety Day – First Aid, Fire Fighting and Risk Assessment competitions;

Schedule of compliance audits and inspections;

TransNet (int ranet) – maintain relevant OHS information accessible to all employees; and

Membership and participation in various industry committees, working groups and Field Days.

In the 2010/11 year the above strategies will continue with a focus on:

health & safety behaviours;

electrical safety;

contractor safety;

Wellbeing and health;

travelling safety; and

fatigue.

Executive Occupational Health and Safety Committee

The Executive Occupational Health and Safety Committee is responsible for:

(i) The establishment and continuous improvement of occupational health and safety systems,

practices and procedures;

(ii) Develop, monitor, review and, where necessary, amend corporate health and safety

objectives and performance measures;

(iii) The effective implementation of occupational health and safety risk management strategies;


(iv) Monitor Industry trends and co-ordinate participation in industry committees and working

groups;

(v) Promote initiatives for the improvement of employee health and safety;

(vi) Facilitate the open sharing of health and safety information;

(vii) Review incident investigations, recommendations and statistics;

(viii) Review occupational health and safety audits and monitor progress on action plans;

(ix) Regularly communicate and meet with workplace management and local Occupational Health

and Safety committees.

(x) Consider recommendations submitted by sub-committees and local Occupational Health and

Safety committees.

Corporate Health and Safety Plan

This Plan sets out TransGrid‟s objectives, targets and key strategies for the year and is the basis for

the development of business unit Health and Safety Action Plans. Progress reports on each business

unit‟s Action Plan are reviewed by the Executive OHS Committee on a quarterly basis.

A Corporate Health and Safety Plan 2010 – 2011 has been developed, communicated and cascaded

through the business where Business Units develop their own unique health and safety plan and

measures based on the corporate plan and the local health and safety risks. Progress on the

implementation of the Corporate and Business Unit Heath and Safety Plans are reported to the

Executive OHS Committee quarterly.

Safety Communications Steering Committee

Communication is an integral component of our health and safety system aimed at ensuring that

everyone is aware of their responsibilities and role in the implementation of our strategies.

The Safety Communications Steering Committee (comprising the General Ma nager/Business

Services, Manager/Health and Safety, OHS Advisor and the seven elected OHS Committee

Chairpersons) assists with the review of policy and procedures through consultation with local OHS

committees. The Safety Communications Steering Committee also develops initiatives to promote

health and safety to maintain a high level of awareness amongst staff and is responsible for

developing and promoting the Quarterly Health and Safety Themes.

Wellbeing

The TransGrid “Wellbeing” Program was launched in March 2010 and its vision is “to promote living a

healthy, happy and productive life by making personal choices that contribute to a healthy and

balanced lifestyle”. The Program consolidates under one banner TransGrid‟s existing “people related”

services available to our employees. These services and initiatives are being reviewed and as

appropriate, added to in the future.

“Wellbeing” provides principles, policies and programs to support employees in the following areas:

Physical Wellbeing - Maintaining healthy and energetic bodies by making informed choices

about exercise, diet and general fitness.

Emotional Wellbeing - The peace of mind, confidence, and self-respect that we achieve by

coming to terms with the full range of emotions.


Social Wellbeing - Recognising the value and contribution of the relationships with family,

colleagues and the community.

Financial Wellbeing - A sense of comfort and security that results from informed financial

decisions that help us achieve our life goals.

Chairman’s Safety Award

The annual Chairman‟s Safety Award recognises an individual or team who has made a significant

contribution to safety in TransGrid throughout the year. The 2009 winners approached a challenging

transformer overhaul project with significant manual handling and lifting activities. Recognising the

health and safety risks the winners developed alternative work methods to those recommended by the

manufacturer/supplier which not only removed much of the safety risk, but produced a lower cost

result.

Annual Safety Day

TransGrid‟s annual Safety Day includes Risk Assessment, First Aid and Fire Fighting competitions for

teams representing all areas of TransGrid. This was held in Wagga in September 2009. In its 52nd

year the Safety Day included events in vital emergency response, fire fighting and risk assessment.

The participation rate on the day was high with participants responding to various injuries and

scenarios.

TransGrid‟s Safety Day helps to reinforce TransGrid‟s emphasis on safety as the number one priority.

The day helps to hone safety skills which positively influence a sustained safety culture in the

workplace.

Schedule of Compliance Audits and Inspections

Compliance audits and inspections conducted to ensure that procedures are implemented in

accordance with legislative and organisational requirements. These include OHS system audits,

random unannounced safety compliance inspections, site conformance inspections, OHS audits on

contractors and team leader audits of pre-work risk assessments. Over the past year a program of

contractor health and safety audits have been introduced on all major projects. Non conformances

identified in the audits are reported and actions are tracked.

OHS Audit reports provided by internal and external auditors reflect a strong OHS commitment,

understanding and performance across TransGrid.

In October 2009 a Workcover audit for self insurance was undertaken, with a successful result for

TransGrid.

TransNet (TransGrid’s Intranet)

TransNet plays an important role in TransGrid‟s communication strategy. All policies, procedures,

manuals and forms are available to all employees electronically via TransNet. This system also

provides other OHS information, including:

Corporate Health and Safety Plan – objectives, targets and key strategies;

Wellbeing programme.

OHS Risk Management Database – including TransGrid‟s Hazard Register, Risk Management

Plan, Work Activity and Workplace Risk Assessments, Work Method Statements, OHS Forms;


Incident Notification System – all hazards, near misses and OHS incidents are notified

electronically which facilitates immediate notification to relevant personnel;

Issues Management System – records all issues requiring action, timeframes for completion

and actions implemented;

Approved Safety Equipment lists – details the Personal Protective Equipment that has been

approved for use within TransGrid;

Listings of First Aid Attendants, Injury Management Co-ordinators, OHS Committees

(members, meeting dates, minutes);

OHS Statistics;

OHS Incident Management procedure; and

Health and Safety Notice Board – includes Safety Alerts, Safety Bulletins and general notices,

links to external OHS websites.

Participation in Industry Committees

TransGrid takes an active role in a number of industry committees and working groups such as

Energy Networks Association‟s Health, Safety and Environment Committee, WorkCover Industry

Reference Group and the Industry & Investment NSW Industry Safety Steering Committee.

Participation ensures that trends and expectations of legislators, industry and the community are

understood and managed effectively. Compliance to these requirements was demonstrated by nil

infringements or prosecutions.

5.2 Serious Electricity Network Accidents (Public)

There were no Serious Electricity Network Accidents involving the public in 2009/10. Initiatives are

addressed in more detail under the Public Electrical Safety Awareness plan report.

Table ‎5.1 – Serious Electricity Network Accidents (Public) Trend

Serious Electricity Network Accidents (Public)Trend

Previous Years Current Year

Category 2005/06 2006/07 2007/08 2008/09 2009/10

Non-Fatal 0 0 0 0 0

Fatal 0 0 0 0 0

Note: Table 5.1 includes Serious Electricity Accidents, which are accidents where electricity was involved in the injuries.

5.3 Actionable Electricity Network Safety Incidents (Public)

There were no Actionable Safety Incidents involving the public in 2009/10.

Table ‎5.2 – Actionable Safety Incidents (Public) on the Electricity Network Summary Trend

Actionable Safety Incidents (Public) on the Electricity Network Summary Trend

Category of Incident Previous Years Current Year

Year 2005/06 2006/07 2007/08 2008/09 2009/10

Total 0 1 0 1 0


5.4 Serious Electricity Network Accidents (Network Worker)

There was one Serious Electricity Network Accident involving a TransGrid employee. The employee

was working at the rear of a secondary systems panel while another employee was performing testing

at the front of the panel. When a test voltage was injected at the front of the panel, the employee at

the rear of the panel inadvertently came in contact with the test voltage. The employee attended

hospital and had suffered no serious injury. The cause was a misjudged proximity to equipment while

test voltages were applied, and work methods were revised so that staff are not working behind panels

while testing is in progress.

There was one Serious Electricity Network Accident involving a TransGrid contractor. A linesman

received an electric shock whilst installing jumpers at a tension structure during construction of a new

transmission line. The electric shock occurred due to induction from an adjacent in-service

transmission line. Safe work practices require the application of portable earths on either side of the

structure being worked on, however one set of portable earths was some distance away from the work

location and the failure to follow safe work practices was the cause of this incident. The linesman

attended hospital and had suffered no serious injury.

Table ‎5.3 – Serious Accidents (Network Worker) on the Electricity Network Trend

Serious Accidents (Network Worker and Accredited Service Provider) on the Electricity Network Trend

Previous Years Current Year

2005/06 2006/07 2007/08 2008/09 2009/10

NF F NF F NF F NF F NF F

Network Operator Employees

1 0 0 0 0 0 1 0 1 0

Network Operator Contractors

1 1 0 0 0 0 0 0 1 0

NF: Non Fatal F: Fatal

Note: Table 5.3 includes accidents where electricity was involved in the injuries.

5.5 Actionable Electricity Network Safety Incidents (Network Workers)

There were no Actionable Safety Incidents involving network workers in 2009/10.

Table ‎5.4 – Actionable Safety Incidents (Network Workers) on the Electricity Network Summary Trend

Actionable Safety Incidents (Network Workers) on the Electricity Network Summary Trend

Category of Incident Previous Years Current Year

Year 2005/06 2006/07 2007/08 2008/09 2009/10

Total 1 0 1 0 0


6. Bush Fire Risk Management

6.1 Bush Fire Risk Management Plan

TransGrid‟s Bush Fire Risk Management Plan is published as Chapter 4 of the Network Management

Plan 2009-14 Revision 1. A previous revision of the plan was subject to external audit and found to

comply with the requirements of the then in force Electricity Supply (Safety and Network Management)

Regulation 2002. Some minor improvements to the plan recommended in the audit report were

included in the subsequent revision and carry through to the current plan.

6.2 Bush Fire Risk Management Performance

In 2009/10 there was one occurrence where a localised fire was initiated by TransGrid assets:

A small grass fire was initiated by a fallen transmission line conductor due to failure of a line fitting on

the 01 Upper Tumut - Canberra 330kV transmission line. This fire self extinguished and was limited to

the immediate area of the transmission line easement.

The following table summarises the performance outcomes, and compares these to the previous

year‟s performance:

Table 6.1 – Bush Fire Risk Management Performance Indicators

2008/09 2009/10

Indicator Target Actual Target Actual

Network assets inspected in bush fire prone areas 100% 100% 100% 100%

Outstanding network risk defects in bush fire prone

areas Nil Nil Nil Nil

Fires where it appears ignition may have been caused

by network assets Nil 1 Nil 1

In 2009/10 there were three occurrences where localised fires were initiated by TransGrid activities:

Spot fires were started by a contractor working on the Wollar - Wellington 330kV transmission

line project. A controlled burn off of stacked timber within the easement was being undertaken

when weather conditions changed. The fire was extinguished with the assistance of the Rural

Fire Service.

A fire was initiated by a contractor working on the 96G Kempsey to Port Macquarie line

project. Sparks from an angle grinder being used on the pole foundation reinforcing cage

resulted in an approximately 15 hectare area of paddock and bush being burnt out. The fire

was extinguished with the assistance of the Rural Fire Service.

An elevated work platform being operated by a contractor working on the Wollar to Wellington

330kV transmission line project came into contact with a Country Energy 22kV line resulting in

the shorting out of two phases and causing a small grass fire. The fire was extinguished by

contractor staff with the assistance of the Rural Fire Service.


6.3 Audits

Technical Performance Assessments (TPAs) are undertaken annually in each of TransGrid‟s three

Regions to audit maintenance and inspection compliance to TransGrid‟s policies. In 2009/10 TPAs

were undertaken in Northern Region (Newcastle Area), Central Region (Metropolitan Area) and

Southern Region (Wagga Area). No bush fire risk non-compliance issues were identified by these

TPAs.

6.4 Preventative Programs

TransGrid‟s preventative program is centred on its routine easement maintenance. Inspection of

transmission line hardware and accessories provides further confidence in the reliability of the system

to not pose a bushfire ignition risk, and to remain safe during any bushfire occurrence in the area.

6.5 Proactive Programs

TransGrid provides corresponding representation to Bush Fire Management Committees as detailed

in Attachment 2 of the TransGrid procedure GD AS G2 006 – Administration of the Network

Management Plan. When required, the meetings are attended by a regional representative providing

advice on matters such as the impact proposed hazard reduction burns will have on TransGrid lines

and recommendations are made on how to protect these assets prior to the commencement of a burn.

TransGrid has also provided advice to the relevant Bush Fire Management Committees that TransGrid

easements can be maintained, particularly in National Park & Wildlife Service and State Forest

managed estates, in a manner such that they can be utilised as Strategic Fire Advantage Zones

(SFAZ). Some easements are now being managed in cooperat ion with these agencies to provide

these zones.

TransGrid‟s Public Electrical Safety Awareness (PESA) plan, which is Chapter 3 of the Network

Management Plan 2009-14 Revision 1, provides a strategy for the communication of the fire hazards

associated with overhead power lines and vegetation and other electrical safety initiatives.

6.6 Aerial Laser Surveys

TransGrid is in the midst of a project to conduct Aerial Laser Surveys (ALS) of transmission lines for

the purpose of obtaining accurate and up to date el ectronic data of these assets. It is only with the

advent of this technology that it has been possible to accurately measure the as built profiles of such

lines. All lines have been surveyed, with data processing continuing with an expected completion dat e

of November 2010 for the availability of all line models.

Results received to date from these surveys have identified spans on a number of transmission lines

in NSW that have clearances to ground below those specified in the relevant Guideline, if they were

operated at their maximum operating temperatures. The possible consequences of low clearances

can include:

flashovers to the ground tripping the line;

flashovers to vegetation that can start a bushfire; and

flashovers to vehicles or people under the line.


A risk management approach has been undertaken to manage these assets in the time until final

designs are prepared and works can be carried out efficiently. This risk management approach has

considered historical loading on the lines and combined this with statistical conductor temperature

monitoring to assess the locations where operation at maximum expected temperatures may infringe

on specified clearances. At no locations do these reduced clearances increase the risk of bushfire

ignition.

It is not considered appropriate to either turn off or de-rate the lines. Such action would place

significant constraints on the operation of the NSW network. The performance of all TransGrid‟s lines

over the past 40 or more years would indicate that there is minimal risk in leaving these lines in

service with their current ratings, providing all reasonable action is taken to mitigate the risk. Actions

TransGrid is taking to mitigate the risks have included raising conductors using alternative insulator

arrangements, adjustment of conductor tensions and localised ground profiling in private property. To

date, TransGrid has rehabilitated eight transmission lines. In terms of managing safety under any

sections identified as having reduced clearances at expected maximum temperatures, treatments

include signage and access barriers depending on the extent of the reduced clearances. TransGrid

continues to maintain interim treatments on six transmission lines pending permanent rehabilitation. It

is expected that processing of the ALS data will identify further lines that will require signage and/or

access barriers and these will be implemented during 2010-11.

Private property owners, National Parks and Wildlife Service, Snowy Hydro Limited and AEMO are

being consulted in relation to the operating issues and risk mitigation strategies.


7. Public Electrical Safety Awareness

TransGrid‟s Public Electrical Safety Awareness Plan (PESAP) is based on a risk assessment of public

safety issues with regard to TransGrid‟s assets. The PESAP is made available to all employees on

TransGrid‟s Intranet “TransNet” and to the public via TransGrid‟s external website, as Chapter 3 of the

Network Management Plan 2009-2014 Revision 1.

The 2009/10 Action Plan for the implementation of the PESAP continued with the three specific focus

areas from previous Plans: Relationship Management, Site Specific Issues and Community

Interaction. Specific highlights for this year included:

A targeted mailout of the TransGrid easement brochure to easement affected property owners

throughout the more populated Central Region. This resulted in improved communications

regarding issues relating to safe practices within easements ;

Information relating to hazards of fire and smoke around transmission lines was provided to

farmers with crops that are likely to be burned at the end of their crop cycle;

All substation sites previously identified with elevated risk factors for security have had new

fencing and other security measures installed. This has resulted in no sites remaining with

elevated risk exposure factors;

The list of Transmission lines with elevated risk factors for public safety due to location or history

of activity has been reviewed, with no additional sites have been identified; and

Continuing progress to meet the timeframes required by NSW Maritime on the risk assessment of

crossings of navigable waterways,

The implementation of strategies is regularly reviewed by a working group of representatives from

each Region and a report is provided to the Executive OHS Committee each year for review.

In addition to regular inspections by field staff, random audits are conducted on all TransGrid

substations at least once every two years by the OHS Advisors to monitor safety conformance and

identify any public safety issues. Identified issues are managed via reports to the relevant managers of

the sites and recorded in the Issues Management System as appropriate.


8. Power Line Crossings of Navigable Waterways

TransGrid has been reviewing its existing waterway crossings for compliance with the NSW Maritime

“Crossings of NSW Navigable Waterways: Electricity Industry Code”. This review has included:

Negotiating with Waterways NSW to re-classify the navigability of a majority of the waterways

presently classified as navigable in the vicinity of the crossing. Many of these crossings are

presently not navigable in any vessel that would cause issues with clearance to the overhead

power line. Once this negotiation is complete, it is expected the number of crossings listed

below will reduce.

Of the crossings remaining, risk assessments are being prepared relating the height of the

crossing to likely vessels, and reviewing the requirements for signage to address any risks

these crossings pose to maritime traffic.

Table 8.1 – Power Line Crossings of Navigable Waterways Summary

Existing

(Number)

New

(Number)

Incidents

(Number)

Crossings

Reconstructed

(Number)

Crossings Identif ied as

Requiring Conversion

to Submarine

Crossings (Number)

Overhead

Crossings 236 0 0 0 0

Submarine

Crossings 0 0 0 0 0

Documents

NSW electricity network performance report · 2015. 6. 26. · 2 | Electricity Network Performance Report 2009-10 Table 1.1 – Network Operator Statistics Network Operator Statistics